


where you come from

by ssuppositiouss



Category: Gravity Falls
Genre: Alternate Universe - Ghosts, Angst, Billdip Secret Santa, Class Differences, M/M, Mutual Pining, Reincarnation, Temporary Character Death
Language: English
Status: In-Progress
Published: 2020-12-26
Updated: 2021-01-02
Packaged: 2021-03-11 08:42:28
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 12,060
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28348602
Author URL: https://archiveofourown.org/users/ssuppositiouss/pseuds/ssuppositiouss
Summary: In the Flatlands of the second dimension years ago, Mason Pines died and his budding romance with Bill Cipher was severed too early.Fifty years later, Bill comes to realize that he hadn't moved on as well as he thought.
Relationships: Bill Cipher/Dipper Pines
Comments: 10
Kudos: 25





	1. chapter one

**Author's Note:**

  * For [goldilocked](https://archiveofourown.org/users/goldilocked/gifts).

**Notes for the Chapter:**

> gift for [goldilocked](http://goldilocked.tumblr.com) for the BillDip Secret Santa 2020
> 
> Let me preface this with how I've never been so inspired by every secret santa prompt I've been given. I have too many ideas for each prompt, just not enough time. And tbh I was a bit overwhelmed having you as a recipient because I adore your writing and your fics?? Like how is this fair to you that you're stuck with me??
> 
> The main prompt I used was "ghost AU" but I snuck slight "historical AU" in terms of the flashbacks/class differences and a small bit of "in vino veritas/drunk confessions" later on, too. ;P
> 
> I'm sorry if it's not exactly what you were hoping for, but I had a lot of fun writing this. Take all my apologies and this fic!

Bill turns, and he regrets.

He can’t tear his eyes away. He sees the Monster reaching into Mason’s chest, claws extended and poised to _kill_. He sees Mason’s eyes widen, his body stiffen. He sees Mason’s lips part in a silent scream, blood trickling from the sides of his mouth.

 _Laugh, Bill Cipher, laugh! You_ love _this kind of pain and gore and_ suffering _, and you hate Mason Pines!_

 _You_ hate _Mason Pines._

He’s _supposed_ to hate Mason Pines, anyway.

This is exactly the kind of horror he enjoys, the pain of the third dimension nobility, the Monsters reigning supreme! The Monster in him loves the little things, the suffering in their eyes, the feeling of loss. It's hilarious, except. . .

“ _For you, Master Cipher._ ”

For him? He didn’t demand this (yet), but do his Monsters _know_? How do they know? Has he been too obvious about his _feelings_?

(Pathetic.)

The Monster grins, yellowed teeth ready to swallow the little gatekeeper. "Master."

“B-Bill?” Mason chokes out.

 _It’s fine, it’s fine,_ Bill repeats to himself, rolling his eye very obviously in case anyone is watching him, in case anyone thinks he’s weak for flinching at this. The Monsters need to know he has power. He isn’t soft to the pain of others, especially not others like _Mason Pines_. And the other gatekeepers can’t think a sight like this affects him, if they’re watching.

(He’s always watching others, it makes sense if they are doing the same.)

Besides. Ghosts can live through injuries like this. Mason’s lived through injuries worse than this. They all have. Bill has the magic to fix it, Ford has the science, and Mason is all too eager to fight with them.

And maybe Mason has lived through worse injuries. Maybe a worse injury should have been the one to kill him. They’re all ghosts, already dead, built to withstand injury, to _last_. But a worse injury isn’t the one that kills him. _This_ is.

He watches Mason crumple, watches him collapse and fall on the ground, unmoving, as he never stands again. The image of the light fading from his eyes burns into Bill’s mind for the years to come. The feeling of Mason's spiritual energy no longer wraps around him, flickering and fading from the air. The Monster continues smiling, waits for its next command.

" _Leave him._ "

“ _Is this not what you wanted?_ ”

_"Leave him."_

“ _His soul is yours now._ ”

_Leave him!_

He swallows the feelings down, the churning in his gut telling him this is the wrong decision, the lump in his throat keeping him from breathing properly. And he laughs.

It’s a mix of disbelief, frustration, anger, hurt. He doesn’t know, and he doesn’t care. All he can do is laugh when the Pines family returns and sees him standing over their precious Mason’s dead body.

He’s dead, dead, _dead_.

The rumors spread that _he_ is the Monster that killed Mason Pines, and he doesn’t refute them.

He laughs as they drag him from Mason’s body, laughs as they accuse him of the murder, laughs when he is released and he is alone.

He laughs, alone.

* * *

Dipper stifles a yawn and adjusts his jacket to ensure his journal stays safely tucked in his pocket. It’s starting to get chilly, with summer drawing to a close and the sun setting, and as much as he wants to get home and get some well-earned sleep, he still has a ridiculously large amount of reading waiting for him. He’s a long way from finding out why he can see ghosts that no one else can see, and his stack of library books aren’t going to read themselves.

Ever since childhood, Dipper has been able to see ghosts.

Their constant pestering caused him grief as he was growing up. The other children teased him for talking to himself, for his clumsiness when he interacted with beings they couldn’t see or hope to understand. He went through a period of pretending the ghosts didn’t exist—what a _joke_ , thinking he was too cool for the spiritual beings that haunted every aspect of his life—but, as the ghosts gravitate toward him, he couldn’t ignore them forever. They always make themselves known to the only other being who can see them.

In retrospect, the ghosts may have spurred his interest in the supernatural.

His footsteps seem oddly loud on the gravel as he walks. Gravity Falls is quiet in the evening. There aren’t many others wandering at this time, the sun setting rather quickly, but Dipper can always use an excuse to clear his head with his frequent nighttime walks—he’s full of jumbled thoughts, unanswered questions for which he can’t find explanations—so he can think of the information he’s found and what it could all mean.

“Hey,” a voice whispers, startling him from his thoughts. He feels the cold brush of fingers on his neck, and he shivers. The touch, the voice, it’s almost seductive, and Dipper feels his cheeks burning for thinking so.

“Umm, hi?” His voice cracks, as usual, and he wonders if he misinterpreted her intentions. He’s not very good at this. He turns to look at her, face heating even more when he sees her pink dress, her pink hair, her pink skin.

When he was younger, he expected ghosts to have different appearances, to not seem so _human_. It took him a while to recognize the difference between someone living and someone dead, and even now he sometimes messes up. This ghost is clearly a ghost because of the singe marks on her dress, the layers of skin peeling from what must have been a fire, the discoloration of her legs.

Have there been any fires recently? He doesn’t think so, and he usually keeps up with Gravity Falls news. A fire in a small town like Gravity Falls would have made the papers.

One day, when he reports on all of this, he’ll have the evidence perfectly laid out, irrefutable.

“Want to spend the night with me?”

Her fingers, though enticing at first, dig into his skin when she realizes he can see her. She’s excited, as though she had gone through the same gestures repeatedly and, until Dipper, none had reacted. That is probably what happened, since not many people can see the ghosts of Gravity Falls.

He hates how lonely the ghosts are. But as an awkward, lonely person himself, he can’t help much.

“Sorry,” he says.

“Sorry?”

She definitely isn’t flirting with him, Dipper decides, willing his blush to fade. He’s stupid for thinking it. “I don’t think I’m your type.”

The ghost smiles at him, sharp teeth glistening in the moonlight as a long, snake-like tongue extends to lick her lips. “But _you’re_ the only person who can see me!”

Dipper has never been good at socializing, definitely not enough to get out of these uncomfortable encounters with the ghosts. He thought, initially, it was his job to bring them to peace, to help them uncover the mysteries behind their deaths.

(But why would they choose someone like him to have this task?)

It only served to make them more miserable, Dipper quickly realized, when he asked them questions they couldn’t answer, when he was prolonging their inevitable passings, when they couldn’t remember details of their deaths and he forced them to relive the experiences. They seem happier without him, most of the time. He loses a lot of sleep trying and failing to get them answers.

One day, he hopes this will all pay off.

The ghosts seem to disappear on their own, though, so he’s taken to leaving them alone if they can’t answer his first few questions, unless they’re particularly persistent.

He takes a step back, tries to smile. “Maybe tomorrow?” Maybe she’ll go to heaven or hell or wherever it is the ghosts have been going. He has theories, but he needs to read more to solidify his thoughts.

He’s tried staying awake and watching the ghosts to see what would happen, but they always leave him or disappear when his eyes slide shut due to exhaustion.

“I didn’t _want_ to die.”

Dipper needs to stay distant from these ghosts, because they’re _dead_ and he’s _alive_ and if he gets attached that’s nothing but trouble, but he can’t resist a mystery when he’s so intwined with their lives already, and he may very well be the only person who can _help_ them. He pats her shoulder very, very awkwardly, the coolness of her dead skin causing him to shiver.

“I’m sorry.” _You’re already dead_. He doesn’t say that, because he learned his lesson the last time. Pausing, then deciding to try his luck, he continues, “Do you know why you’re still here?”

Maybe this is the ghost he can help. If he knows why she’s still around, if it’s something unresolved, if there’s something he can do. . .

“No.”

They never know. Dipper needs to stop asking, hoping. He can help them if he understands more, but he’s just as blind to the truth as they are, though not for lack of trying.

The problem is that the ghosts love to follow him. A number of ghosts enjoy chatting as he tries to sleep, and even more have followed him into public restrooms. He bites his lip at the memories: his high-pitched scream had scared the other patrons and gotten him banned from that restaurant.

He isn’t sure why so many people are dying close to Gravity Falls enough that their ghosts are hanging around, nor is he aware of the reasons behind their desire to follow him, but his constant lack of answers spurs his insatiable thirst for knowledge.

So far, he has theories but no results.

When Dipper enters the Mystery Shack, he is satisfied to note that there are no ghosts waiting for him. He breathes a sigh of relief and makes his way to the table in the kitchen, ready to follow his usual, rather monotonous routine. The ghost does not follow.

He is left alone.

* * *

The renowned Gatekeeper Academy is where Bill first hears of Mason Pines. Mason and Mabel are the nephew and niece of the distinguished Pines twins, the _strongest_ master gatekeepers of the third dimension. They were raised under the sheltered, protective guidance of a family knowing exactly where they want their children to end up. There is no dislike for the Pines nobility.

They are _pure_ ghosts, born in the third dimension itself instead of originating in the human world or the second dimension. Their blood makes them stronger, supposedly, the best force to fight the Monsters of the second dimension. They are, essentially, royalty.

As a _pure_ ghost, Mason is a boy with spiritual energy that could rival some of the professors, maybe even some of the trained gatekeepers themselves.

In a twisted way, he also has none of the physical prowess to match.

He is nearly as ambitious as Bill himself, confident in all the wrong ways, but he is hardly a force in battle.

Mason has messy hair and a sardonic smile and large brown eyes, and it’s the first time Bill sees a boy and feels his heart twist in such a pleasant way. He doesn’t know what to make of these thoughts, exactly, but he knows that it feels nice looking at Mason, who is enough of a mess that Bill can’t look away.

He’s horribly plain, really. Pale skin spattered with freckles, lips bitten so hard he’s drawn blood, suit perpetually disheveled. But Bill’s golden gaze follows him anyway, because it is expected but also because. . . there’s something about Mason he wants to understand.

(But it doesn’t matter what it is he wants to know, because Bill is just a Monster, and Mason is a noble _Pines_ boy.)

They don’t talk to each other, of course. They’re in different classes, literally and socially, and Bill isn’t meant to fraternize with the people from the capital, especially people with family who have been here for generations. Bill is an orphan from the enemy Monster dimension, a mixed breed that already has a lot to overcome, unable to fully build himself out of his part-Monster background.

And he has a very clear deformity marking him as part-Monster, too, one he can’t hide behind his long blonde hair. His gouged-out right eye with the unhealed surrounding skin wins him no favors in the third dimension. His background makes him stronger than any _pure_ gatekeeper, but it fuels the resentment more than anything.

He hears the rumors before he can even speak to Mason. Different feelings start to brew, replacing his initial awe.

The Pines twins have such _promise_.

The Pines twins will be the rising _stars_ of the Gatekeeper Academy.

The Pines family, yet again, has brought _prodigies_ to the third dimension.

 _Again_.

Bill has trained to be that person, has worked and worked and _worked_ to gain favors, to become powerful, to be invincible.

He is the strongest gatekeeper, the strongest ghost in the third dimension.

 _He_ is the one who has the strength, the power, the promise.

For Bill, who grew up trying to break out of the limited expectations placed on him, who was the boy with natural talent that the Academy originally adored, these rich twins showed up and ruined everything. Even Ford, who Bill was working so hard to impress, cannot resist his only _family_.

Mabel Pines has the skill with magic and weapons that her brother lacks, but her interest is more in the politics of the Academy and of gatekeeper society as a whole. She will be a leader, _their_ leader, one day. She writes herself out of Bill’s story, leaving behind a boy with more expectations on him than ever expected of Bill, who could have actually reached them. Mason is not as smart, nowhere near as skilled with magic or weapons.

Somehow, Bill is forgotten.

And Bill doesn’t _like_ being forgotten. He’s their most powerful gatekeeper, he’s half-a-Monster and ready to _hurt_ anyone in his way!

He can hear the rumors in the hushed voices, the mocking glances. Bill can read people well, and he knows that people are comparing them, are thinking less of the Monster hybrid from the second dimension Flatlands. But Mason is the one ruining Bill’s plans, taking Ford away from him, stealing his sponsors, his chances of getting out and building himself up and becoming the leader he is meant to be.

His existence stains Bill’s heart.

He doesn’t like this Mason boy, he decides, when he meets the gaze of Mason-from-the-capital and feels the crushing force of his spiritual energy. He doesn’t like this Mason boy, who the upper classes adore because of his upbringing, who effortlessly gains the favor of teachers and superiors despite his lack of skill. He doesn’t like this Mason boy, who awkwardly stumbles past him in the hallways, oblivious to his effect on Bill.

“Oh, sorry,” Mason says one day, when they both reach for the same library book. He stares right at the empty space where Bill’s eye would have been. “William, right?”

Of _course_ , he’s William Cipher, recognizable by his missing _eye_! Of _course_ , a stupid noble would do this!

"Charming. Did they teach this behavior to you in your baby noble finishing school?" Mason's face turns red. Yes, he _should_ be embarrassed; it's rude to stare without Bill giving permission! Stare for his skills and how attractive he is, not for his _eye_. "Why do _you_ care, Pines?"

Mason seems surprised at the harsh reaction—probably unused to having someone not _immediately_ love him—and he drops the book, so Bill is able to take it. "Seriously? You're the top of our class; I figured we'd meet sooner."

"Rich boy wanted to meet the Monster with one eye?"

"I. . ." He fumbles for words, and Bill snickers. "I was curious, yes."

"Curiosity is a funny thing." Bill sneers, looking down at Mason, pleased at their height difference. At least he's above Mason in some way, ha! "It can get you _killed_."

"If you're rude to everyone you meet, it's no wonder people don't like you, William."

"You call it rude, I call it familiarity! Call me Bill, and I'll call you Pine Tree!" He smiles wide, fake, nearly laughing at Mason's discomfort. "Not to be _sappy_ , but we're already the best of friends, can't you tell? How about _eye_ see you out?"

"If you think this is friendship, I pity your companions," he mumbles flatly, though his eyes flicker again to Bill's deformity. "Bill."

"Funny. I'd say we all pity a certain Pine Tree instead."

Mason snatches the book from Bill's hands, giving him the dirtiest look he can give with such a red face.

Bill hates this boy.

(he hates him he hates him he _hates_ him)

* * *

The woods in the human town of Gravity Falls are a desolate place, a prime area for rifts in the human reality to leak ghost Monsters from the second dimension Flatlands (and they used to, until Bill told them to lay low for a bit). The sky is a mix of purples and oranges, the temperature cooling rapidly despite the summer heat mere moments ago.

The human world can be beautiful, Bill decides. Especially as he plans to destroy it all as an energy source for his Monsters in the second dimension!

After all, everyone handles things differently, and the Pines family is still not over the death of their _beloved_ Mason. Bill is _definitely_ over that stupid kid, and he’s more than ready to move onto his grand plans.

Plans involving the destruction of the human world and the move of the Flatlands to the third dimension. Clearly the Monsters know how to handle power; the third dimension is as lost and hopeless as it had been fifty years ago, _still_ affected by the death of their stupid noble.

He used their distraction to hide from people’s gossip and strengthen his Monster army. He was kicked out of the Pines family inner circle when Mason died. Though they couldn’t _prove_ it was related to him in any way, they had wanted an excuse to be rid of him for decades. They’ll all regret their actions, soon enough.

No one will be expecting him.

The plan had formulated when he first graduated from the Academy—ranked below the Pines twins and forced to work at their side—and it had solidified when his Monster underling noted his resentment and murdered Mason Pines. His friends from school were all-too-eager to fight back against people who hurt them, their rumblings with Bill during their Academy days finally something worth executing.

He might as well finish what his feelings unwittingly started.

Might as well take credit for what happened.

(He won’t.)

Ford’s reports detail that an increasing number of new ghosts have been passing through this area before they can be brought back to the third dimension to find peace. He’s been tracking the movements of any Monsters that escape the dimensional rifts into earth, and Bill has been bored enough to steal Ford’s research and sneak a few ghosts for his own energy, with no one the wiser.

Ford has his own suspicions, but Bill has so many secret agendas that his boredom is the last thing on anyone's radar.

An increase in spiritual activity in Gravity Falls could simply mean more human deaths in the area (which is what the ghosts in the third dimension believe), but Ford insists that the ghosts have been gravitating to this area of the human realm after dying elsewhere. He just hasn’t found the reason why—he hasn't cared for the human world since it hasn't been central to the war effort.

But someone or some _thing_ is attracting the Monsters here, and Bill is bored and hungry for power and secrets. He doesn’t mind breaking a few rules to get what he wants, and he's commanded the Monsters to stay away until he's explored the possibilities.

But a Monster from the second dimension is supposed to attack tonight despite Bill's demand. Considering how many ghosts have been in this area recently, Bill is surprised at how long it’s taken for a Monster to disregard his instructions and come here.

When humans die, their ghosts remain in the human world until they are purified by ghosts like the Pines family—arguably the most well-known gatekeepers, the most _powerful_ —so they can be sent to a further beyond. If the ghost cannot be purified, or if the ghost loses all semblance of hope and humanity, it instead becomes a Monster and is killed or sent to the second dimension by the gatekeepers.

Monsters can consume ghosts either waiting to be purified or already purified. And Bill can understand why, what it means to be desperate and empty, coming from the Flatlands himself, the perfect mix of the second and third dimensions. The more ghosts consumed, the more powerful a Monster can become. The third dimension, of course, is not a fan of their numbers dwindling. Hence the war.

His ties to both worlds are why he will make an excellent master of both.

He _understands_ everyone.

He’s near a shack in the middle of a clearing by the woods, a place Bill wouldn’t have initially pegged as a popular location for Monsters to attack or ghosts to visit. There aren’t enough ghost souls here to devour, not enough to feed a rabid Monster desperate to feel whole and human again.

And Bill can smell a ghost _begging_ to be devoured.

He licks his lips.

“Hey,” a voice purrs, a ghost in all pink coming near him. Her aura tells him that she’s been dead for a few months, and she probably made her way to Gravity Falls in that time. Perhaps Ford’s research is going to prove something after all.

Bill smirks at her, his eye narrowing so she knows he’s dangerous. She should stay away. She slides her fingers into his hair, her breath cold on his ear.

“I’m going to eat you,” Bill tells her, mainly wondering why his luck got him stuck with such weak souls. The woman laughs, oblivious to the significance in Bill’s words. He isn’t sure what she thinks he means, but he doesn’t really care to explain himself.

“You’re more fun than the other guy, at least.” She adjusts her burnt skin, pressing layers back into place from where it is grotesquely peeling. “Whatever. I mean, I guess it’s great that he’s _alive_ ”—well that’s just _interesting_ , isn’t it? Bill's smirk becomes lethal—“but I sure as hell am _not_ , and now I see _you_ aren’t, either.”

“The _other guy_!”

Bill gives her no more time to speak, allowing his Monster instincts to overcome him. He unhinges his jaw, sharp teeth clamping into the ghost’s body, and _devours_.

She tastes exactly like every other ghost he’s consumed—dead and bland.

A waste.

Hunger not even close to being satiated—but whose hunger really _could_ be when they have only meals like this; at least he becomes more powerful this way—Bill sniffs at the air, searching for another ghost with decent spiritual energy. A Monster wouldn’t come here against his demands unless there was someone worth collecting.

And then he senses it.

A regular Monster in the vicinity, as he’d been expecting, and also, he pauses, inhaling again, a mouth-watering _human_ soul.

The human is not dead, that much is obvious, and Bill feels a small surge of excitement.

“Well, well, well!”

He hasn’t killed to eat for a while. He’s kept a low-profile, only consuming ghosts instead of killing humans and eating their ghosts afterward. For a soul like this, though, Bill doesn’t mind hunting and killing. The power he would get is well worth the effort.

He can’t tell if the low-class Monster that is arriving is after the human or if they just happened to be in the same vicinity, but suddenly Bill is starving. He can almost taste the human’s spirit in the air.

The human has abnormally high spiritual energy. So much, in fact, that Bill is surprised it hasn’t already been attacked by hungry Monsters. The aroma of the human’s soul is like nothing he’s known a human to have before, though there is something oddly familiar about it.

Bill _wants_ it.

It’s a little overwhelming, the way the energy burns free. Usually, people try to shield their energy, so they aren’t as easily recognized. Humans, of course, wouldn't know to do that.

This raw power is almost. . . enticing. The Monster part of him _craves_ this type of soul, relishes in the power he can _steal_.

This person is probably what attracted all the ghosts, and he or she is probably what has attracted the Monster coming to this area. Bill isn’t completely surprised that this has slipped past the third dimension’s radar, since losing Mason Pines to an unnecessary battle with a no-name Monster deepened the war between the second and third dimensions, Monsters and ghosts attacking each other more than ever. It is permanent death to those who originated as humans, but to the _pure_ souls or _pure_ Monsters, there is a chance of reincarnation.

The death of so many ghosts means little to Bill, though.

And Bill, with his second-dimension background and proximity to Mason’s death, only fuels the fire—and he wears his lost rank with pride, because he’s going to rule over them all, one day, just like he’d planned before (because) Mason’s death ruined it all.

He has about a minute before the Monster is set to appear. He smiles at the thought of taking its prey, of becoming more powerful in secret, of ending this war and reigning supreme and showing them exactly what it _means_ to be a _Monster_.

He will be the most powerful, even as a hybrid, and he’d never feel how he had before, when Mason died.

* * *

“You can’t like him,” Kryptos says, and though their voice isn’t unkind, there’s something underneath their words. He wonders if someone’s put them up to this, if they are looking out for him, if people have been talking. It’s hard to tell, when he’s worked to blank countenance at all times. Bill has his friends, but he’s still working on getting a read on all of them, as they’re all Monster-hybrids and Bill is their leader.

They all want more out of their lives. The Flatlands have no hope for them, and the third dimension treats them like this.

It doesn’t help that Mason is the walking example of their mistreatment.

He doesn’t know what expression is on his face, whether he’s in disbelief (he doesn’t like _Mason_ , he can’t like him) or disgust (he could never _like_ Mason) or disagreement (he can like who _ever_ he wants). Mason has been compared to Bill in every way since Bill enrolled in the Academy, especially now that they have been paired to work with Stan and Ford Pines after they graduate the Academy. They’re close in age, from opposite backgrounds, different histories that ended up intertwining.

They are, sometimes, friends.

Bill wonders if this assignment is because the Pines want to keep an eye on him.

“It’s a good thing I don’t, then.”

“Bill.” Kryptos speaks in monotone, but there is emotion in there that makes Bill angry. “I grew up with you, I know what you look like when—”

“It’s nothing,” Bill insists, irritated. “Whatever I feel about him, it’s not. . .”

Mason is the boy whose interactions with him had never considered his own nobility and Bill’s Monster background—it’s different from how his other friends treat him, because Mason just doesn’t act properly compared to those who know Bill’s background and mock him for thinking he could ever achieve more.

Mason has expectations of Bill that don’t relate in any way to his upbringing, he’s just always seen _Bill_. He slips up sometimes, but he’s also seen the way the nobility regards Mason for not living up to expectations. Mason makes a certain face when that happens, where he puffs out his cheeks and. . .

Bill hates the fondness creeping into his thoughts, despises the way his heartbeat picks up, even though he knows his heart is only for show because he’s never been alive and he is very much dead.

“Of course,” Kryptos says, and there’s a look in their eyes that Bill has seen countless times.

“Of course,” Bill repeats, irritated.

“People talk, though, and he’s bringing too much attention to you. He’s not in your social circle. The only thing worse for someone like him would be a full Monster.”

“A human could be worse,” Bill jokes, unable to stop his harsh laugh, the slight bitterness seeping into his tone without his consent. Can the other Monsters hear it? “It wouldn’t even see him.”

He’s not as good as everyone else in the third dimension, apparently, but he could be much worse.

Talking to Kryptos doesn’t provide any comfort, but at the very least they've pointed out that he isn’t doing _everything_ completely wrong. Sure, he didn’t become a master immediately upon graduating from the Academy (and though he hates hates hates himself for that failure, he is slightly relieved that he doesn’t have to play that role because he doesn’t think his future plans align with that anymore).

Everyone has to know he’s a better fighter than Mason (but when they practice fighting each other, Mason’s defeats are so easy, and they collapse next to each other and smile when the battle reaches its standstill).

_Mason glances at Bill, the slightest dusting of pink on his cheeks, as his hands fidget around the books in his arms. He gives Bill a sort of half-smile, one that makes Bill feel warm, and he stops fiddling with his stack of books and parchments to wave clumsily. He brings his hand back to his collection of readings and glances away when Bill doesn’t wave back, but Bill feels that gaze move back toward him again._

“We don’t need this attention.”

“I agree.”

"The other Monsters don't need this attention." Bill rolls his eye; he can do whatever he pleases, no matter what Kryptos tells him. “You can’t like him, Bill.”

 _I know_. “I don’t.”

**Notes for the Chapter:**

> Please let me know your thoughts, particularly if the world-building is confusing in any way. It was inspired by bits of "Soul Eater" and bits of "Bleach" and even bits of "Voltron", oddly enough.
> 
> The three chapters of this fic have all been written and just require editing, with the goal of everything published by the end of this week as I edit between work shifts.
> 
> (as always, feel free to talk gravity falls and billdip on [tumblr](http://ssuppositiouss.tumblr.com))
> 
> Happy holidays and Happy New Year, friends!!


	2. chapter two

**Notes for the Chapter:**

> This took a bit longer to edit than I initially planned, last part to come out at some point this week (with another oneshot I wrote instead of editing this lololol, boarding school AU, anyone?)

They’re not really walking together, but they are close enough to each other that Mason’s entourage must find Bill even more suspicious. Mason seems to enjoy Bill’s company, though, actively seeking him out for the littlest things, even though their first interactions had been rocky.

Bill can’t quite decide what to do with this information, the fact that they’re such different people, they’re not meant to _know_ each other, and they do.

(And they get along more than Bill would like to admit.)

“Only the head gatekeepers can tear rifts between the dimensions,” Mason reads aloud as he walks, messily jotting notes on one of the many spare pieces of parchment he carries. “A power set forth by the head scientist several decades ago, Stanford Pines.” His eyes light up whenever he learns something new—not that Bill has noticed this _before_ , he’s just observing _now_ —and the current topic of study in their classes is the second dimension.

A subject so _near_ and _dear_ to his dead heart.

“And the Monsters,” Bill adds under his breath, several steps behind. With a wave of his hand, he could easily open a rift into the second dimension. It adds to people’s suspicions of him, makes it more difficult when he wants to sneak back. Because Monsters cannot survive without the ability to travel dimensions for _food_ , it makes sense. “But why would anyone want to travel to the _Flatlands_?”

Mason shuts his book loudly and turns to face Bill. “You’ve been there.” It isn’t a question.

Obviously. “Why? Looking to become a Monster meal? You have a Monster right _here_.” He grins, wide and predatory.

“No!” He glares daggers at Bill for suggesting such a thing, as he always does when Bill jokes about his meals. “I just mean, you have an unfair advantage on the exams.”

“ _That_ ’s your concern?” Bill laughs until his sides start to hurt, ignoring the strange looks directed at both of them. Mason’s priorities have always been a riot. It’s probably why he does so poorly in his training, though it doesn’t matter how badly he performs, since he’s a Pines and he’ll get what he wants regardless. “Not the fact that at any time, I can tear an opening into a dimension set on destroying little _ghosts_ like _you_?”

Mason swallows, walking faster to keep up with Bill despite the uncertainty in his voice and his eyes. “You wouldn’t let that happen.”

He’s sure he _would_. The chance to get rid of Mason Pines, in a way that’s entirely not his own fault? It would be stupid not to follow through.

“I’d very much let you die, Pine Tree.”

Mason ignores the _true_ statement, continuing, “The same way you let me get hurt in our training?”

Catching Mason from too-powerful blasts and keeping him from getting too injured are different from letting him die in the Flatlands. “Those instances don’t count,” he says, finally.

“If we went, it would be a good learning experience. For research purposes.”

“For research purposes.” Bill rolls his eye. They’re in the middle of a war, and Mason’s curiosity is going to get the better of him. “I have people to _torment_ , Pine Tree, and you want me to waste my time babysitting you in the Flatlands.”

“It wouldn’t be _babysitting_ ,” Mason insists, offended. “I can fend for myself. We’re in the same classes.”

They’re in the same classes, but Mason is better at theories and history, bookwork and writing. He’s notoriously pathetic at fighting and defending himself, areas where Bill exceeds expectations because of his Monster heritage. Bill has _power_ beyond their comprehension, skills they don’t even _know_.

But they need to _keep an eye on Bill_ instead of letting him _help_.

“Someone’s _rushing_ into things!” Bill gives him a look. “You went from studying to asking your _rival_ to bring you to another dimension. Have something you want to say to me, Pine Tree?”

Mason blushes bright, beautiful red. “No one trusts me to go anywhere.”

He’s been clear about his complaints before. He’s a Pines, meant for greatness, so they won’t bring him anywhere _dangerous_ , particularly when he’s not the greatest at even the basic techniques. It doesn’t help that he’s so focused on studying with a _Monster_ , too.

“I can’t leave you alone in the Flatlands,” Bill says, slowly. If Mason dies there, it would be traced back to him for sure. He _unfortunately_ can’t let it happen.

Yet.

And Mason’s spiritual energy is bounding, limitless, formidable. One _moment_ in the second dimension and the Monsters all around them would sense his presence and want a taste. He isn’t good at hiding his presence, clumsy in his shielding tactics, and Bill isn’t about to waste any of his power to protect a _Pines_.

“Then will you answer my questions? There’s so much the books don’t discuss. How often do you go back? Do you still have a home there? Do you know other Monsters? Have you gone to the human world, too?” The questions spill from his lips like blood from a large wound, and Bill wonders what he has to do to make Mason stop talking.

Somehow, taking him to the Flatlands seems like the lesser of two evils.

“What’s in this for me?” he interrupts, staring into Mason’s large brown eyes.

That shuts him up. “You’ll take me?”

“If you offer something good.”

“I. . . don’t really have anything,” Mason admits.

“You don’t have a _single_ thing you could offer a _Monster_ like me?”

There’s a lot Bill could take from him: Mason’s name carries a lot of weight, and a favor from a Pines could forward Bill’s place in the third dimension tremendously. But if Bill is the one to bring him to the second dimension, he could gain a lot of sway over the Monsters who are already unhappy and waiting for an excuse. The Monsters have been looking for a new leader, and Bill would be the perfect Monster-ghost for the job.

The third dimension has proven, time and again, that Bill will never be enough for them.

(The dirty looks he is getting now, for standing so close to precious Mason Pines, are proof.)

“I know!” Bill snaps his fingers, like this idea hasn’t come to mind before, like he hasn’t been planning ways to get this out of Mason.

“What?”

“I’m _hungry_ , Pine Tree.”

Mason's confusion is evident, since ghosts have no need for meals, nutrients. Monsters consume ghosts and souls to feed them power and strength, things that ghosts already have. It deepens the rift between the two species, because ghosts can never understand what Monsters in the Flatlands go through.

“You want. . . food?”

As a child, Bill starved for being so different. His form was too ghostlike for the Monsters, but too Monsterlike for the ghosts. He is subtle now, when he eats. He doesn’t need as much as a full-fledged Monster, but he still needs to travel to the human world for nourishment. When no one is looking.

Deep down, Mason has to know this. It’s not like Bill is _lying_.

“If you’ll feed me, I’ll show you a little of the Flatlands.”

“That. . .” Mason bites his lip, and Bill can’t drag his eyes away from the action. “Next time we’re in the human world, we could probably. . .” He’s mumbling so much to himself, Bill can only catch snippets.

“Just one meal.” Bill grins. “A Monster’s got to eat.”

“And you’ll take me to the second dimension?”

“Sure! But don’t sound too excited, kid, but this deal is on the table for another minute only! I have _exams_ to prepare for.”

“What would you eat?” But he’s reaching for Bill’s hand to make this deal, excitement at the prospect of knowledge overpowering the obviously poor deal he’s making. “Humans eat snacks. Dessert cakes, I’ve heard.”

Their hands connect—warmth from Mason’s touch making Bill tremble—and Bill barely gives Mason time to shake his hand when he tears into the air with a loud laugh, clawing a rift into existence and dragging them both inside.

As always, the rift is icy cold, and Mason clings to Bill as they pass through the black, effervescent gash in the dimensions. Claws and hands try to grab at them as they pass, beings trapped in the rift that can never escape, snagging onto their uniforms and tugging, _begging_ them to stay in the rift forever.

They walk into the Flatlands within seconds.

“Wow. . .” Mason stumbles when the rift closes, pulling away from Bill to look around in wonder. “ _Wow_.”

A sliver of a silver moon exists in the black sky, barely illuminating the gray desert sand underneath their feet. Dead trees surround them, a world of monochromatic grays and blacks and whites. In the distance, the sounds of screaming and crying are carried by the slight breeze that rustles their uniforms. Everything appears blurry, fizzled out like the dying world it is becoming.

But both the second and third dimensions need to survive.

“This is the second dimension.” Bill waves a hand unceremoniously. “Nothing but desert, flat lands, and flat dreams.” He can’t help the bitterness in his tone.

It seems, no matter where he goes, he’s unwanted. But he’ll show them all exactly who Bill Cipher really is!

“Bill. . .”

“Monsters roam around, eat each other, eat the new ghosts who come here after death. It’s very _gruesome_.” Bill smiles, enjoying the look on Mason’s face. “I can tell you _all_ about it.”

"Yes, please!" Though the gore doesn't seem to appeal to him, Mason writes everything he can on his stupid spare parchments, questions bubbling from his lips. “Are there societal structures here, like in the third dimension? Where are most of the battles for the war? What would happen if this world collapsed? What about—”

“I don’t spend much time here, Pine Tree.” He only visits occasionally, to see how things are going with the Monsters, to keep up appearances of caring, to build up his reputation. “You know I fight for the third dimension now.”

He fights for himself, now. It hasn’t been on the forefront of his mind, but when he meets up with Teeth, or Paci-Fire, or Xanthar, he knows he can achieve more.

The cold, dry air makes Mason shiver. “Where are you from, if you don’t mind me asking?”

He minds. He minds a _lot_. Mason has very little sense of what are considered respectable questions to ask, so curious about everything around him, noting every detail, asking about every little plant and creature he sees. Bill explains in short bursts, with as little detail as possible.

The Flatlands can be what humans consider Hell, if he really thinks about it. Though the place isn’t a fiery pit of misery, the cold, starving, loneliness and the very small likelihood of escape are a miserable end for any humans who give up their hopes. Existence is a battle to second, permanent death.

“There are no buildings here, like in the third dimension. Everyone wanders until they find a new meal.”

The third dimension is not Heaven, but an in-between, to keep ghosts on the correct path to Hell or Heaven.

As a child, the product of a dead ghost executed for his union with a Monster—and his father will never reincarnate, as he was human once before, and the ghosts _knew_ this when they killed him—Bill had nowhere he truly belonged, and he stayed in the Flatlands because it was where he was spawned, wandering alone after his mother’s death. He learned to summon rifts on his own, learned of his power by himself, learned he didn’t look monstrous enough to stay, though he wasn’t ghostlike enough to live in the third dimension either.

Bill scowls.

The existence of these dimensions is so _boring_. It only makes sense that there is a war and the second dimension is unhappy with their role to play. It only makes sense that creatures of both worlds would want an escape.

Mason explores the Flatlands with the wide eyes of a human child, touching the trees, the sand, the bones, with a morbid curiosity that brings the slightest feeling of lightness to Bill’s chest. “When did you leave?”

“When I wasn’t enough.”

Mason drops the parchment he’s holding. “You’re the top in our class, now. You. . . matter to m—”

“When _it_ wasn’t enough!” He laughs, loudly and harshly. “No need to _over_ react, Pine Tree. Calm yourself.” Bill doesn’t want to talk about it anymore.

Mason keeps his questions focused on the Flatlands, getting the hint. His spiritual energy soars as he learns more and more, and he awkwardly attempts to provide comfort.

Bill senses the other Monsters beginning to creep toward them, slinking toward the clear power source. He is surprised at how long it takes, since they’ve been in the second dimension for a while now, but he supposes a war wreaking havoc on an already poor dimension leaves them even weaker than ever.

Bill has a high spiritual presence, as well, more than the others here but nothing compared to Mason Pines. The Monsters sense this, and they are wary.

He communicates with them in their language, ignoring the look of excitement in Mason’s eyes. “ _The boy is mine_.”

“ _You brought a gatekeeper into our home!_ ”

“ _And not for us to feast?_ ”

“ _Cipher, what is the meaning of this?_ ”

Bill grins. “ _Let me show you my power over this ghost scum, and we can change the war in the Monsters’ favor_.”

Mason swallows, biting his lip again. “What are you saying? Who’s there, Bill?”

“I’m telling them to go away. Don’t worry, Pine Tree.” Bill elbows Mason until Mason gives him an uneasy smile. “ _You think you all can take on a Pines?_ ”

“ _You expect us to trust_ you _, a half-breed?_ ”

“ _Did you bring him here to give him our_ secrets?”

“ _I am taking part of his soul to show the third dimension who we are, who_ I _am,_ " Bill says, confidence in every word. " _Defeating a gatekeeper is nothing for me._ ”

“ _So you spy on the ghosts, instead?_ ”

“ _You brought a_ Pines _gatekeeper to our lands?_ ”

The Monsters creep closer.

“ _Watch me!_ ” Now that they are more visible, clearer to Mason, Bill puts on the act. “I wanted to wait until we were back, but I need power now, if we have to fight them.”

“They’re coming here?” Mason squeaks, suddenly very worried. He _would_ be, since he isn't as strong as Bill. “Should we just leave? Let’s head back home.”

“I can take them, but I’m hungry.”

Mason chews his bottom lip. “I-I have some spirit plants with me, but—”

Bill almost finds it endearing how ridiculous Mason sounds. Ghosts don’t need nourishment as Monsters do, so his cluelessness is _hilarious_. As a part-Monster, there is only one meal he can consume: ghosts. “Pine Tree.”

Realization hits. “Oh!”

“You promised me,” he says, laying it on thick, acting breathless and tired, like promises between ghosts and Monsters mean _anything_. “ _Come closer and watch, residents of the Flatlands_.”

“That sounds like a bad idea.” His paranoia kicks in. “Won’t the other Monsters get hungry, too? What if they go after both of us because you aren’t strong enough, and I die, and you’re their next meal, and you—”

“You said it yourself, I wouldn’t let anything happen.” Bill frowns. “I’m also the most powerful gatekeeper you will _ever_ meet, don’t act like it’s so _easy_ to take me down!”

“You’re not even a gatekeeper yet.” Mason sticks out his tongue. “Let’s go back? Away from the Flatlands? I can. . . _feed_ you, then.”

“ _He won’t even resist my power_.” Bill places a hand on Mason’s shoulder. “I have so much more to show you. We'll be okay.”

Mason swallows, shoving his parchments in his pockets and strengthening his resolve. “One meal,” he repeats, determined. “Okay. But how will you—”

Bill is sure the sight will traumatize him, but the awe in Mason’s eyes instead makes him shiver in delight. Bill’s mouth splits his jaw so his teeth can lengthen and sharpen, and his eye goes fully black to match the hollow space of his missing right eye. He clamps his mouth onto the soft, sweet junction between Mason’s neck and shoulder, messily slurping the energy Mason barely conceals, tearing pieces of his spirit away from him.

He is _delicious_.

The Monsters around them cheer, surprised and pleased at how easily a _half-breed_ is able to overcome what must seem like a powerful gatekeeper. If only they knew.

“ _How do we know this isn’t for show?_ ”

Bill grins as he swallows, body pulsing with new power, satiated and pleased, enjoying the feeling of a warm ghost pressed so close to him, feeding him, giving him this _energy_. He doesn’t normally stop after eating part of a soul, but this is Mason Pines.

“ _Is this for show?_ ”

He snaps his fingers and sets the Monster who questioned him and the surrounding trees aflame, then latches his mouth back to Mason’s neck.

Bill takes enough to _hurt_ , but he knows Mason will survive. Mason is powerful, and ghosts can heal unless the injuries are too great and the soul is fully damaged.

It takes all of his resolve to stop feeding. The Monster part of him wants nothing more than to finish.

Mason needs to lean on Bill for support for the rest of their exploration of the Flatlands, but all around them the Monsters whisper of the potential of the half-breed, the potential they might have in this war.

“ _Bill Cipher took a_ Pines _. You can sense it, can’t you?_ ”

Bill laughs.

(But Mason laughs, too, and for the first time in his existence, the Flatlands seem just a bit bright.)

* * *

Dipper takes his notes, the minutes passing too quickly for his liking as the night begins to creep on him. He’s accustomed to getting little sleep, losing himself in his research, but he’s a couple days into his dedicated no-sleep-until-the-books-are-done time, and he’s very, very tired. His exhaustion even makes it feel like the room is shaking, and his eyes sting, begging him to just _sleep_ , but he can’t. Not yet.

Maybe a quick walk around the shack will help. He stands and stretches. “Seriously, Dipper. You have three books to go!”

The floor of the shack creaks as he walks, joltingly loud in the otherwise silent night. He tugs his jacket back on as he makes his way outdoors, breathing in the chilly air. He’s completely alone. The moon shines brightly and a breeze ruffles his jacket.

The large, open sky makes Dipper close his eyes and just _breathe_. There are no ghosts around him. It is peaceful.

Something heavy strikes his back.

Heat immediately surges through his body, and it feels like his back is _burning_ and pain is spreading through him. His head spins. The cracking noise startles him into awareness, though he finds it difficult to ignore his spine as it _screams_ at him.

He can’t breathe, he can’t think, he can’t move, it hurts so badly.

He tries to focus on moving his fingers, to distract himself. _One_ , _two_. . .

Trying to ignore the blinding pain merging with the specks of light dancing across his vision, Dipper stands up shakily. He pretends it isn’t his blood making his shirt wet.

“Should’ve read your book,” he jokes to himself, though he can feel the heat of tears threatening to escape his eyes. “Breaks are for the weak.”

The ghost stands tall, towering over the Shack easily, its two sets of arms pulled into fists. Its body is all black, purple splotches discoloring its rough skin. It mimics an insect, with its many arms and its curving exoskeleton. Dipper ducks away from the hit aimed in his direction, stumbling out of reach.

_What the—_

It is a type of ghost Dipper has no intention of learning more about (yet). It’s a _monster_.

His head pounds, reminding him that it is stupid to move around when he hurts so badly, but he _can’t hide_ in the Shack when the ghost-monster _thing_ is probably going to crush him inside it!

 _They’ve never looked like this before_!

Dipper’s eyes dart around the dirt until they rest on a large stick lying on the dead grass. He grabs it immediately, desperately, chucking it with all of his strength.

The hit could have been painful to a human if clocked with such force, but it is barely acknowledged by the ghost.

It screams something intelligible, and Dipper almost sighs in relief that it is focused on something _else_ , except the scream turns out to be a form of attack.

“Oh no. . .”

The ground begins to quiver as the monster screeches again, an odd beam of light charging in its mouth.

“Bad idea!”

Head pounding as he trips on the uneven ground, he decides the best chance of his survival is in running away. He’s never dealt with ghosts such as this one, and he is barely able to protect himself from minor annoyances like ghosts following him into bathrooms. There’s no way he can handle this. His research told him _nothing_ about monstrous ghosts.

No ghosts have told him about monsters before.

But why is the monster interested in him in the first place? He’s just Dipper, a silly little human who sees ghosts. The human ghosts who follow him, he can almost understand; he would be the same, confused after death, craving companionship, wanting just to find peace.

A giant monster, though? This giant monster gets nothing from someone like him. Nothing he can think of, anyway.

Large hands reach for his body, and the ghost monster is in front of him in seconds.

He jumps out of the way just as the ghost’s claw scratches at his leg. Dipper bites back what would have been an undoubtedly high-pitched shriek—instead it had been a repressed groan merging with tears springing from his eyes, which are squeezed shut—when his flesh tears and the monster’s fingers scraped against his bone.

His leg feels nearly _torn open_.

He can feel blood gushing through the wound, the sticky warmth pouring through his fingers in a puddle on the ground. Jumbles of curses spring from his lips. He can barely hear his own whimpers over the ringing in his ears, the pounding of blood in his head. He can’t hear anything other than the incessant, maddening ringing.

The spirit shrieks again and swipes at Dipper, and he clamors backward and tries to stand.

His vision goes white. He can’t feel his leg anymore, a numbing throb overtaking his whole body. He moves, dragging his leg uselessly as the monster’s hands tear at his back, adrenaline keeping him moving. A cool breeze contrasts with the heat escaping his body.

He isn’t going to survive.

The realization stings. He is going to become one of the ghosts he’d always seen, the spirits he’d ignored as they wanted more life, beings he complained about because he couldn’t understand them. He never fully understood them, either. He never finished his research.

Dipper’s vision begins to blur as the monster aims at him again. Something hot wraps around his body, and he can only feel the heat burning through him. He can’t breathe.

He falls.

* * *

It is after another reprimand, a disappointed lecture from Ford Pines, that the fight happens. They are both alone in the war room, their superiors having filed out to leave them to discuss their failures. They are probably lingering, listening. Mason can’t be left alone with a _Monster_.

Of course, as usual, everything is _Bill’s_ fault. The Monster that got away was because of Bill. The failed reconnaissance mission was because of Bill. The injuries Mason obtained were because of Bill.

And what does Mason have to say about it?

He's embarrassed. He's knowing. But it's not enough.

“I hate fighting with you!” Bill shouts, scathingly, fists clenching. He’s been better about unwittingly summoning fire, but he feels the familiar heat in his hands, the ache to _destroy_ something. The Monster in him is _screaming_.

“Fighting with you isn’t high on my list of favorite past times, either, Bill,” Mason agrees, crossing his arms. “But I don’t—”

Bill wants to stop himself from talking, but he’s so frustrated, so angry. “ _With_ you,” he repeats. _Burn it, destroy this, break everything_. _Hurt him._ “On the same team.”

If he weren’t working with a _Pines_ , maybe, _maybe_ , he’d be better off. His mistakes would be his own, and he could build his reputation separately. The relation to Mason has reduced him to this, to someone who has to destroy everything.

He can’t take over the third dimension like this.

(And sometimes, when he and Mason are talking, he doesn’t know if he wants to.)

Mason looks more than a little hurt and Bill’s stomach twists and he wants to swallow all his words back. He doesn’t. Mason shakes his head and starts yelling back, “I don’t want to be on the same team as you, either!”

“Then who would fight your battles for you, Pine Tree?”

Mason is about to say something, but Bill beats him to it.

“You scraped through graduation because of your title.”

There is a pause, and it is clear Bill has overstepped a line—they talked about this once, late at night, and Mason admitted to his feelings of inadequacy, and Bill had feigned indifference over his glee that Mason at least _knew_ —before Mason’s eyes, clearly blurring with tears, take on a new harshness.

And Mason bounds right over the unspoken rule, the one thing he is never allowed to discuss. “Maybe _I_ don’t want to fight with a _Monster_ like you.”

A beat passes. Then another.

“Leave then,” Bill spits out, ignoring the hurt bubbling inside him at Mason’s words.

“I will!”

He’s seen these feelings in Mason’s actions, occasionally, unwittingly, but to hear it actually said brings a new level to _whatever_ their relationship is. But he has to have the last word. He isn’t going to be saddened by a _stupid_ Pines boy.

“Won’t fight with a Monster? Pathetic. Little. Pine Tree. You aren’t strong enough to fight one, anyway.”

If Bill had known that their argument would spur Mason to jump into the battle in the second dimension, he would have grabbed him and forced him to stay behind. Instead, he followed Mason to the Flatlands, and his anger and his resentment and his desire to _hurt_ Mason as badly as he was hurt echoed through the air. ( _Is this what you want, Master?_ And he blindly, angrily, demanded, _Yes!_ )

If Bill had known that their argument would trigger a series of events that lead to Mason’s death, he would have bitten back his pride. (False confidence, because Mason has been here before, he was fine when they were exploring together in their Academy days. “Oh, _you’re_ here.” A smirk. “We all know you wouldn’t survive a minute with a Monster unless another _Monster_ can save you, Pine Tree.” A hurt scowl. “Let’s see about that, _Bill_!”)

If Bill had known that their argument would be the last time he would ever speak to Mason, he would have said something different. (“What’s that you said about yourself, Pines? Need help after all? From a _Monster_?” Mason’s lips parted in a silent scream, blood trickling from the sides of his mouth, his head tilting in the slightest of nods even after the Monster makes it clear he’s acting on Bill’s feelings. “B-Bill?”)

Instead, the argument replays on a loop—leave then, you wouldn’t survive a minute with a Monster unless another Monster can save you, need help after all—and Mason dies in front of Bill’s eyes.

“ _For you, Master Cipher_.”

Mason dies because of him.

* * *

Bill laughs rather maniacally, when he first sees the human, bleeding and stumbling because of a _weak, low-tier_ Monster. It reminds him of human fragility, the weakness of ghosts to Monsters, why he should be proud of his background of being part-Monster.

(A pride he’s constantly reminding himself to feel, because the third dimension shuns him, and the second dimension questions him, no matter what he does. He doesn’t quite belong anywhere, and he has to forge his own path to simply exist. People follow him, but do they _trust_ him?)

The man is limping—or maybe walking slowly and dragging a damaged leg would be a more accurate description, humans are so _pathetic_ —probably knowing the futility of his situation and dealing with it in the only way he knows how.

He licks his lips like the predator he is, taunted by human skin and a human _soul_ in a way he hasn’t felt in years. He can only imagine the taste, the heat, the _power_. The human’s jacket and shirt are torn through, and pale, almost-white skin shines with sticky blood. He’s so close to death, to becoming a consumable ghost.

He notes the high spirit energy of the human, the smell quite intoxicating when merged with blood and sweat. He likes that the human has a strong spirit—it seems familiar in its own way—it makes devouring him much more entertaining. He’s never found a human spirit so tempting before.

Bill spends only a second deliberating on whether or not to take the human for himself, for the Monster is ready to stake claims to such a tantalizing soul.

Its long tongue slithers down the human’s body, and the human reflexively leans into the touch. It must have been a relief to the person, after all, to finally give in.

Bill snaps his fingers, and the Monster falls back, dropping the human so he slides downward into a bloody heap in the grass. “ _This one’s mine!_ ” he commands.

As the Monster recedes, Bill surveys the area. It isn’t too much energy to float, but it would be a lot easier to fight a Monster if he can stand on a solid surface. He straightens out his suit as he lowers himself to the ground. Maybe the human is a pretty one, and he should look his best if he’s going to devour—

“Who. . . are you supposed to be?” is the curious phrase turned upon Bill the second he stops levitating and lands on the ground, voice cracking as his pitch rises. Bill can feel the suspicious glare directed at him. Even in pain, this human is pushing through to question him. “Your suit is a bit. . . old.”

“Excuse _you_.” Bill feels his mouth pull into a scowl, out of habit, his dead heart twisting. The blatant disrespect! Bill is going to devour his soul and make it as _painful_ as possible!

The boy’s voice sounds uncomfortably familiar—enough that Bill’s instinctive reaction is to grimace, after all—but Bill has been around for nearly a hundred years so everything is familiar, really. His witty retort dies on his tongue, _the who are you_ replaying in his mind on a loop as he tries to figure out where he’s heard this voice before. The human’s spiritual energy wraps around him, wild.

“Wait!” Bill’s voice startles himself.

The human stares at him expectantly, as he tries to pull himself upward into a sitting position. The grimace on his face would normally make Bill laugh, but he’s rather distracted. “What?”

“You can _see_ me!”

Only one other person in the human realm has ever seen a ghost since Bill’s started sneaking here, and she died not too soon after. A Monster had swallowed her soul, its grin wide and toothy, its long tongue wrapping around her tiny body and pulling her in and _crushing_ her so her spirit was easier to access. It was the sort of horrible thing that used to make him laugh at night (the kind of stories he would tell Mason to see him squirm and laugh at his reaction).

But he only visits the human realm out of boredom, now, if he’s hungry and he has nothing else to do to forward his plans.

He doesn’t like to admit that witnessing death in such a way throws him back to that fight fifty years ago. He can’t show weakness, not when he has a role to play, a goal to reach.

The ground begins to rumble, and the boy’s “Of course I can, you—” is cut off as a horrid shriek pierces the air. Bill sees the boy pressing his hands to his ears, feels the Monster’s ghost energy fluctuating like a pressure in the air, trying to knock them down.

The boy’s own spiritual energy continues to burn around them, and the Monster laughs, licking its lips. Its yellow eyes focus on Bill, then zoom immediately to the human broadcasting power for all the ghosts and Monsters in this area. Its lips pull into a smirk, then it lets out a piercing wail.

The human stumbles, but he rights himself and ducks out of the way of the monster’s swing. It isn’t a graceful move, and he skids on the ground while the Monster roars.

“What kind of ghost—”

Bill isn’t sure how strong this Monster is, if it is a creature born of the second dimension or created from disillusioned human ghosts. He can beat it, easily. He has to _crush_ it, now that he knows it ignores his commands. The human, on the other hand. . .

“Ghosts never looked like this before,” the human mumbles, out of breath and probably to himself. Bill hears him anyway.

“Before?” Bill demands, curiosity piqued. “You’ve _seen_ others?” He knows it’s not the best time to be interrogating this human, but this is important information. The human is jotting down these thoughts in a notebook though, _right in the middle of battle_ , blood literally _dripping_ down his back. “What is _wrong_ with you?”

This human is strange, with his spiritual energy _burning_ through the air, with his ability to see and sense ghosts. Whatever he knows must be useful.

“You’re the weird one!” he grumbles, loud enough for Bill to hear. Bill bites back his retort—his mind is racing too much for him to have been proud of it anyway, but this human is impudent, and _sassy_ , and Bill wants to _knock_ him down a few pegs—and focuses his sights back on the task at hand.

He debates whether it’s worth protecting a human so determined to anger the Monster wanting to eat his soul and wipe him from existence, ultimately deciding that a little effort may be worth the human’s spirit in the end. He charges his magic in his palms, blue electricity crackling as a warning.

“Move out of the way, human!” It’s time for a real fight.

The human startles at the sound of Bill’s voice. Their eyes meet (he seems lost in thought, it’s such a bad time to be lost in thought), and Bill’s heart rate speeds up, unbidden, so he glances away. This momentary exchange is enough time for the Monster to shriek again, and the human stumbles again at the Monster’s call.

“You should leave!” He’s wheezing, very clearly exhausted, but he has the energy to spout nonsense, it seems. “You won’t go to your afterlife like this!”

Bill rolls his eye at the human, who notices Bill’s attitude and glares back defiantly. Despite his careless appearance, Bill knows what he’s doing. He couldn’t have gotten this far in the third dimension without having _skill_ , especially considering his background and the hatred that followed him.

This Monster is ignoring Bill’s demand, though, and that just won’t do.

He sends a blast of fire at the Monster, and it wails.

The incredulous look on the human’s face lasts all of two seconds—barely long enough for Bill to recognize the look—before he clumsily scrambles to find a weapon of his own. Unfortunately, the outside of his shack is not rife with weaponry, and he pulls a fork from a dinner bowl on the windowsill of the porch, brandishing it with grace that comes with fighting with a piece of cutlery while on an injured leg.

“Move, ghost!”

 _What an imbecile_ , Bill thinks, then pauses at the familiarity of such a thought. Odd, because how many stupid fleshbags has Bill really seen in the past fifty years?

Unfortunately, the human’s strength can only go so far with a mortal weapon.

The fork, obviously, does little to even scratch the Monster, but the action is enough to anger it. It swings its arms again, forcing the human backward and into the outside wall of the shack. He lets out a pained grunt, a sound that makes Bill’s stomach feel uneasy.

Odd.

The life of a reckless human means little to him, and losing a source of that much potential power is just wasteful. Neither should warrant such a strange reaction from his body.

Bill shouts, “Stay there!” hoping that, this time, the stubborn boy will heed his warning. He glances back to check that the human is recovering, sighing in surprised relief as the human blinks his eyes open.

He jumps up and toward the Monster, directing fire to the Monster’s face. He ignores its pain as he lands on the roof of the shack, debating the best course of action to take.

He does want to interrogate, since Ford insists there’s been increased spiritual activity here, but the Monster count has not increased to match that change in activity. Is it because of the presence of this human? What made this Monster ignore Bill’s clear demands? Is there something _else_ going on, keeping other gatekeepers away as well?

As Bill is pausing to think, the human _thoughtlessly_ decides to take action again. Bill doesn’t get the chance to yell at the human before the human is thrusting his stupid fork into the leg of the beast.

The Monster wails, shifting direction immediately, wrapping its hands around the human’s body and _squeezing_ as it lifts the human upward to examine its prey. Bill can _hear_ the harsh hold of the Monster, the pained gasp that the human makes, the coughing, the _choking_.

Bill feels. . . nauseous. For a moment he is frozen, thrown back in time, past the death of the human girl, watching as the Monster murdered Mason—

“ _Mmm_ ,” the Monster interrupts Bill’s thoughts, a slimy tongue sliding across its lips. Its language can only be heard by others from the second dimension, and Bill can hear the grin in its voice. _Delicious_. “ _A strong soul falling to_ me.”

 _A strong soul_. . .

 _A pained shout_. . .

 _The smell of blood and death and Mason_. . .

Bill’s hands heat in fire and power, a cataclysm of magic surrounding them as he pulls himself out of his mind and back to reality (it’s been fifty years, he repeats to himself, _fifty years, fifty years, fifty years_ ). He’s in the present but he isn’t.

“Souls only fall to _me_ ,” he corrects, fury burning through him. “I am your _god_!”

He doesn’t know when he snaps his fiery fingers, doesn’t feel himself pulling the trigger to cause death, doesn’t notice his magic piercing the monster. But he does see the Monster’s grip loosen, does see the human fall. He hears the human’s body hit the ground, hears the screeches of the monster as blood drips from its hand. He feels the human’s energy continue to blaze, feels the intense desire of the Monster to devour that energy.

 _End it_ , the words wrap around him like a soft blanket, shielding him from the harshness of the past reality. _End it_. And Bill does.

He poises his hand to snap his fingers again, watching the recognition in the Monster’s eyes before Bill _snaps_ and his energy pierces its forehead. There is no shout of pain, just blood, then light, then nothing.

The powerful energy of the Monster fades—no soul for Bill to even consume, nothing to make this worth the energy he wasted—though that of the human lingers in the air.

Bill wavers on his feet, vision blurring for a moment as he struggles to stand. His head pounds, and he clutches a hand to his forehead, massaging it as though his actions make a difference. He wants to collapse with the energy he’s used. He hates and loves using his stronger magic, but it takes such a toll on him that it’s difficult to ascertain its worth. His body begs him to fall.

But he won’t fall. Now that he’s being watched, he needs to show his strength.

He’s stronger than this.

He’s Bill Cipher, the Monster hybrid from the second dimension, the one who will rule over them all.

The human’s breathing is ragged, but he’s undamaged. Bill’s instincts are telling him to leave the human behind as he is, to let the boy wake up without truly interacting with a ghost. But Bill won’t be able to rest if his questions are left unanswered, if he doesn’t learn about this powerful soul.

So he stands, and he watches.

He waits.

There’s an unpleasant churning in his stomach, looking into this boy’s dazed eyes (a soft brown so common it shouldn’t linger in his mind). The moonlight highlights the brown, and Bill has the overwhelming desire to vomit.

The human is sweaty and there’s a small trickling of blood from his forehead—bangs blown back to show he is marked with that same constellation birthmark—more blood over his eye and down his cheek, dirt and pine needles stuck to his skin. His hair is a curly mess of tangles and even more pine needles. He’s covered in blood, leg injured, clothes torn, back scratched open.

He looks exactly like Mason Pines.

(Bill told himself he’d recognize that spiritual energy anywhere, and he’d tried to forget once that energy had been wiped from existence.)

The human has pale, bruiseable skin, scratched and stained with blood. He's beautiful.

The Monster in him _sings_.

**Notes for the Chapter:**

> As always, I am open to critique or just any comments/thoughts. I always enjoy getting to talk with everyone <3 Thank you for reading this far (and for commenting on chapter one!)
> 
> find me on [tumblr](http://ssuppositiouss.tumblr.com) to talk about billdip or gf or anything ohoho
> 
> Happy New Year! I hope 2021 is amazing to all of you!


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